1. Technical Field
The disclosure relates to a vehicular lamp used for an automobile and so on.
2. Description of Related Art
In general, it is possible to switch a vehicular lamp between a low beam and a high beam. The low beam lights up a close range with given illuminance, and light distribution regulations are specified so as to avoid glare for oncoming and preceding vehicles. The low beam is mainly used while a vehicle is running in an urban area. Meanwhile, the high beam lights up a wide range and distant places ahead of the vehicle with higher illuminance, and is mainly used while the vehicle is running at high speed on roads with less oncoming and preceding vehicles. There is a problem that although the high beam gives a driver better visibility compared to the low beam, it causes glare for other vehicle drivers and pedestrians in front of the vehicle.
In recent years, an adaptive driving beam (ADB) technology has been proposed, which allows dynamic and adaptive control of a light distribution pattern of a high beam based on a surrounding state of a vehicle. The ADB technology detects existence of preceding vehicles, oncoming vehicles, and pedestrians ahead of a vehicle, and reduces light in areas corresponding to those vehicles or pedestrians. Therefore, glare for those vehicles or pedestrians is reduced.
As a system that realizes the ADB function, a shutter system in which an actuator is controlled, a rotary system, an LED array system, and so on are proposed. In the shutter system and the rotary system, although it is possible to continuously change a width of an extinguished area (a shaded area), the number of extinguished areas is limited to one. In the LED array system, although a plurality of extinguished areas may be established, a width of the extinguished area is restricted within an irradiation width of an LED chip, thus causing discreteness.
The applicant proposes a light scanning system as an ADB system that is able to solve these problems (see Japanese Unexamined Patent Application Publication No. 2012-224317 (JP 2012-224317 A), Japanese Unexamined Patent Application Publication No. 2010-6109 (JP 2010-6109 A)). In the light scanning system, light is made incident on a rotating reflector (a blade), the incident light is reflected at an angle corresponding to a rotation position of the reflector, and the reflected light is scanned in front of a vehicle. At the same time, lighting and extinguishing of a light source is changed depending on the rotation position of the reflector. Thus, a desired light distribution pattern is formed ahead of the vehicle.